title: Structural and functional studies of FKHR-PAX3, a reciprocal fusion gene of the t(2;13) chromosomal translocation in alveolar rhabdomyosarcoma.
abstract: Alveolar rhabdomyosarcoma (ARMS) is an aggressive pediatric cancer of skeletal muscle. More than 70% of ARMS tumors carry balanced t(2;13) chromosomal translocation that leads to the production of two novel fusion genes, PAX3-FKHR and FKHR-PAX3. While the PAX3-FKHR gene has been intensely studied, the reciprocal FKHR-PAX3 gene has rarely been described. We report here the cloning and functional characterization of the FKHR-PAX3 gene as the first step towards a better understanding of its potential impact on ARMS biology. From RH30 ARMS cells, we detected and isolated three versions of FKHR-PAX3 cDNAs whose C-terminal sequences corresponded to PAX3c, PAX3d, and PAX3e isoforms. Unlike the nuclear-specific localization of PAX3-FKHR, the reciprocal FKHR-PAX3 proteins stayed predominantly in the cytoplasm. FKHR-PAX3 potently inhibited myogenesis in both non-transformed myoblast cells and ARMS cells. We showed that FKHR-PAX3 was not a classic oncogene but could act as a facilitator in oncogenic pathways by stabilizing PAX3-FKHR expression, enhancing cell proliferation, clonogenicity, anchorage-independent growth, and matrix adhesion in vitro, and accelerating the onset of tumor formation in xenograft mouse model in vivo. In addition to these pro-oncogenic behaviors, FKHR-PAX3 also negatively affected cell migration and invasion in vitro and lung metastasis in vivo. Taken together, these functional characteristics suggested that FKHR-PAX3 might have a critical role in the early stage of ARMS development.
authors.affiliation: Center for Molecular Biology of Oral Diseases, University of Illinois at Chicago, Chicago, Illinois, United States of America.
authors.forename: Qiande
authors.initials: Q
authors.lastname: Hu
authors.forename: Yewen
authors.initials: Y
authors.lastname: Yuan
authors.forename: Chiayeng
authors.initials: C
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002448:Cell Adhesion; D002454:Cell Differentiation; D002465:Cell Movement; D049109:Cell Proliferation; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D057809:HEK293 Cells; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000556:secondary; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008969:Molecular Sequence Data; D019042:Muscle Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D032446:Myoblasts / Q000378:metabolism; D041681:NIH 3T3 Cells; D009368:Neoplasm Transplantation; D015514:Oncogene Proteins, Fusion / Q000235:genetics* / Q000378:metabolism; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics* / Q000378:metabolism; D021381:Protein Transport; D018232:Rhabdomyosarcoma, Alveolar / Q000235:genetics* / Q000378:metabolism / Q000556:secondary; D015533:Transcriptional Activation; D014178:Translocation, Genetic
chemical_list: C085126:FOXO1 protein, human; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; D015514:Oncogene Proteins, Fusion; D000072041:PAX3 Transcription Factor; C489409:PAX3 protein, human; D051761:Paired Box Transcription Factors